Process for the manufacture of cements and similar products



M. L. BOILLOT AND J. DAUDIGNAC.

PROCESS FOR THE MANUFACTURE OF CEMENTS AND SIMILARPHODUCTS.

APPLICATION FILED JUNE 28. 91s.

1 ,332,4;22 Patented Mar. 2, 1920.

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STATES PATENT OFFICE.

MAURICE LUCIEN BOILLO'I AND JEAN DAUZDIGNAC, OF MOU'IIERS, FRANCE.

PROCESS FOR THE MANUFACTURE OF CEMENTS AND SIMILAR PRODUCTS.

AppIication filed June 28, 1918.

ent elements of the said products, to whatever combination they belong.

It is universally admitted and recognized in the present manufacturethat the temperature in the interior of the burning kiln must not reachsuch a degree that the materials introduced into the same should fuse,and in all kilns hitherto used, even in the most modernones, regulationof the said temperature is exceedingly difiicult, and it is necessary tostop the operation at the beginnin of vitrification of the materialsused. This results in the serious drawback that, after each taking outof the kiln, there is obtained a large quantity of unhurnt materialowing to inequalities of temperature in the various zones of the kiln.Moreover, there is a risk of the vitrified materials adhering to thewalls of the kiln, as the latter cannot provide the temperature requiredto keep the melted materials in a liquid state,

or enable a complete homogeneity of the product to be insured.

The electri furnace already commonly used in electro-chemistry andelectro-metallurgy, is remarkable by the flexibility of its working; itmakes it possible to obtain any temperature,from a few hundreds ofdegrees to that of the volatilization of coal, with the possibility ofmodifying its Work.-

in at any moment or bringing it to the most suitable temperature for themanufacture in question.

In the process according to this invention, the constituent materials ofthe cement are first ground, then thoroughly mixed together Without aprevious treatment,

introduced into the-electric furnaoe wher e they are completely melted.I Owing to the considerable temperature obtained, the materialscompletely react on each other in order to form calcic silicates andaluminates,

Specification of Letters Patent.

Patented Mar, 2, 1920,

Serial No. 242,422.

and transmit by radiation and conductivity part of their heat to theadjoining elements which melt. Moreover, the molten mass is keptconstantly in motion by the action of the are produced under the foot ofthe electrodes, and by the descent of the comparatively cool mixtureinto the molten mass. This results therefore in an energetic mix inginsuring perfect homogeneity of the finished product which can thus bemade, ac-

cording to the mixture employed and to the products to be manufactured,pasty liquid or extra fluid by superheating.

The accompanying drawing given merely by way of example, shows anelectric furnace in vertical section.

At its lower base is arranged the hearth 1 made of refractory materialsand provided at the sides with a lining resisting the destructive actionof the molten products. The hearth plate 2 of the furnace is constitutedby a conducting pis (rammed earth) resting on a current-supplying plateconnected to the conductor bar 3. The arch of the hearth 1 is connectedto the shaft 4 of the furnace and leaves a passage for four electrodes 5connected by cables 6 to the other conductor bars 7. The number ofelectrodes varies according to the intensity of working to be obtained,the nature of the current, the method of connection and the shape of thehearth. The electrodes 5 are operated by means of winches 8.

The materials brought ona truck 9, are discharged into a receiver 10where they are dried by the passage of the hot gases escaping throughthe throat 11, fines 12 and the nace where they are gradually heated as.

they descend, by the action of the heat of the furnace and of the gasesof the melting hearth, and the reactions between the va-.

rious elements take place.

The molten-final-product after the operation'" has been properly carriedout, is suddenl cooled by water or by air, and cast at regu ar intervalsthrough the orifice 15 into movable molds.

According to circumstances and to the object to be attained, the furnace(an more- 1 Che! over vary in its constructional details, it could befed by a continuous current or by an a ternating current.

By means of this process, and With the use of an electric furnace, it ispossible to obtain hydraulic lime and any desired artificial cements,quick-setting, half-slow, slow-set ting, puzzolan, synthetic, with anyindexes of fhydraulicity.

In the same Way, it is possible to obtain any desired hydraulicproducts, of any composition, according to the mixtures to be treatedand to the reactions in the furnace, and oi colors varying from white toblackish gray, by the addition or suppression of reducing agent in themixture.

This process by fusion in an electric l urnace does not a't 'ect thequickness of setting uts, it is possible to obtain, e mixtures,quick-setting molten t is to say quiclcsetting molten artificialcements.

lt is also possible to obtain hydraulic products or" variable density bythe addition or-subtraction or metal oxide, chiefly terruginous, and anysilicates of lime, alumifill ll si natcs of lime and silico-aluminatesof lime,

and therefore to imitate any natural or artiiicial cement.

The hydraulic products cast are of two classes:

lhose Which alter the cooling disinte grate in the air and are convertedinto impalpalde powder which does not leave any i'eriduo on screen No.80. These products ca 31 011, be packed at once Withoutany at], banaltreatment; the products removed from the electric furnace are perfectlyburnt, as they are molten, and have a great resistance to tension and tocompression and are. also hi hly suitable for grinding".

2. 'l 1e products remaining compact during slow or sudden cooling, whichare treated sul'isequently liite clinltcrs of cement kilns.

'lhc ditlerence found between the products oi these two classes is dueto proportions of silica, alumina and lime used in the mixturcs, and thetime oi fusion.

The quality of a hydraulic product, and therefore its ('mumcrcial value,depend not only on careful manufacture, but also on the cluunicalconstancy of the layers in the quarry used, and on the necessity oftreatcomparatively fusible materials at the temperature of cementltilns(1250 to 1-100 degrees lilydraulic qualities are imparted or clayeylimcstoucs generally used, by the addition of limestone or lime.

The electric furnace in which very few substances resist fusion, makesit possible to use n'iatcrials which are too refractory for ordinarykilns, and generally speaking, any raw umi'crials the elements of whichcan enter into the composition of hydraulic to clays Leas es products orbe simultaneously eliminated at the high temperature which it develops.

Among the raw materials treated by this process, can be used: i

1. Any primitive rocks: gneiss, micaschists, chlorite-schists and hornblende schists.

2. Eruptive and volcanic rocks; granite, quartz, porphyry, trachyte,basalt, lava, etc., and products of decomposition, sandstone slate,puzzolan, sand, comprising moreover any silico-aluininate of thefeldspar class, zeoliths, micas, chlorites, scliists, clays.

3. silicates of lime, iron, groups of augite hornblende and l olivine.

l. Natural silicates 015 alumina such as andalousite, staurolithe.

5. Natural aluminates and bauxite.

6. Pure, magnesium containing' or claylimestones and any calciumcompounds such as sulfates, phosphates, tungstates, chloride, fluoride.

7. Combinations of iron, manganese, titanium, tungsten, chromiumexisting in the state of impurity in the materials hereinbeforespecified, or by addition to the mixtures used.

8. Slugs of blast furnaces, acid or basic steel furnaces and electricfurnaces with fei'roelloys.

These materials are used in accordance with their analyticalcomposition, with connection of on e or another of theeonstituents, andby addition or subtraction of one or more elements in order to arrive atthe desired composition of the final product. The question of fusibilityplays a part therefore only in the economical[use of the electricsenergy required for the reaction, and the quantity of coal to be fuseddepends on the quantity of oxide which have to be reduced. It istherefore alwaysv very small, with rare exceptions.

By generalizing its application, thecement industry would cease todepend on 110 special deposits or quarries, but only on cheapelectrical. energy produced by Waterfalls. lVater power resources arehowever very considerable throughout the Whole world, and their positionis generally that of the deposits of all the materials to be used.Building of cement mills utilizing this process is therefore independentof the quarry to be Worked, but depends only on the place whereinstallation of hydraulic 120 force will be the cheapest and where thetransport of finished products is easy.

Having now particularly described and ascertained the nature of our saidinvention and in What manner the same is'to be per- 1 7 formed. wedeclare that What We claim is:

1. The process of manufacturing cement and the like. consisting ingrinding and mix jug the constituent material, melting the same in anelectric furnace, keeping the 1159 molten mass in motion by the actionof the the electric ar until the same is discharged electric arc nntilthe from the furnace.

2. The

in an electric furnace, utilizing the heat of the furnace to heat thematerials. While chargng the furnace therewith, and keeping the moltenmass in motion by the action of process of manufacturing cement t1 andthe like, conslstnig 111 grinding and 1111K mg the constituent material,melting the same same is discharged from the furnace.

In testimony whereof we affi'x our signan'esin presence of twowitnesses.

MAURICE LUCIEN BOILLOT. JEAN DAUDIGNAG.

Witnesses:

CHAS. P.'PRESSLY, J. LEBSEUR.

